In vitro ultrasound characterization of coronary arteries at 50 MHz

Ultrasonic attenuation coefficient, wave speed and integrated backscattering coefficient (IBC) of human coronary arteries were evaluated, in vitro, over the -6 dB frequency bandwidth of 35-68 MHz, for a total of 44 artery samples (normal and diseased). The wave speed measurements (average over the entire vessel wall thickness) varied from 1507 to 1746 m/s with a population mean (± one standard deviation) of 1575.92 (±52.29) m/s. At 50 MHz the attenuation coefficient, 5.08 (±1.31) dB/mm, varied between 3.0 and 8.6 dB/mm. Over the frequency range of 35-68 MHz, the frequency exponent of the attenuation coefficient, 1.53 (±0.18), varied between 1.11 and 1.88. IBC results for the media layers are within 2.0×10^-3 and 8.0×10^-3 (Sr·mm) ^-1, while those for intima and adventitia fall between 10^-2 and 10^-1 (Sr·mm)^-1. Plots of IBC as a function of depth show the potential for using IBC to differentiate between normal and diseased vessel walls